Add test for BlockDeviceInputStream

app/src/test/java/eu/depau/etchdroid/utils/blockdevice/BlockDeviceInputStreamTest.kt

@@ -0,0 +1,110 @@
+package eu.depau.etchdroid.utils.blockdevice
+
+import com.github.mjdev.libaums.driver.BlockDeviceDriver
+import com.github.mjdev.libaums.driver.file.FileBlockDeviceDriver
+import org.junit.Assert
+import org.junit.Test
+import java.io.File
+
+class BlockDeviceInputStreamTest {
+    @Test
+    fun testWithCommonParams() {
+        runReadTest(
+                10L * 1024 * 1024,  // 10 MiB
+                512,
+                2048
+        )
+    }
+
+    @Test
+    fun testWithWeirdBlockSize() {
+        runReadTest(
+                10L * 666 * 2 * 666 * 2,  // 10 MegaDevils
+                666,
+                2048
+        )
+    }
+
+    @Test
+    fun testNoPrefetch() {
+        runReadTest(
+                10L * 1024 * 1024,  // 10 MiB
+                512,
+                1
+        )
+    }
+
+    fun runReadTest(testDevSize: Long, testBlockSize: Int, testPrefetchBlocks: Int) {
+        val testFile = createTestFile(testDevSize)
+
+        try {
+            val testDev = createTestBlockDevice(testFile, testBlockSize)
+            val inputStream = BlockDeviceInputStream(testDev, prefetchBlocks = testPrefetchBlocks)
+
+            // Read first bytes
+            Assert.assertEquals(0, inputStream.read())
+            Assert.assertEquals(1, inputStream.read())
+            Assert.assertEquals(2, inputStream.read())
+            Assert.assertEquals(3, inputStream.read())
+
+            // Seek within prefetched buffer
+            val skipBytes1: Long = 2L * 0xFF - 4
+            Assert.assertEquals(skipBytes1, inputStream.skip(skipBytes1))
+
+            Assert.assertEquals(0, inputStream.read())
+            Assert.assertEquals(1, inputStream.read())
+            Assert.assertEquals(2, inputStream.read())
+            Assert.assertEquals(3, inputStream.read())
+
+            // Seek outside prefetched buffer
+            val skipBytes2 = 5L * 0xFF * testPrefetchBlocks - 4 + 100
+            Assert.assertEquals(skipBytes2, inputStream.skip(skipBytes2))
+
+            Assert.assertEquals(100 and 0xFF, inputStream.read())
+            Assert.assertEquals(101 and 0xFF, inputStream.read())
+            Assert.assertEquals(102 and 0xFF, inputStream.read())
+            Assert.assertEquals(103 and 0xFF, inputStream.read())
+
+            // Mark stream to get back here later
+            // Implementation ignores readlimit so anything works
+            inputStream.mark(0)
+
+            // Seek to EOF
+            val remainingBytes = testDevSize - (4 + skipBytes1 + 4 + skipBytes2 + 4)
+            Assert.assertEquals(remainingBytes, inputStream.skip(remainingBytes * 20))
+
+            // Ensure EOF
+            Assert.assertEquals(-1, inputStream.read())
+
+            // Seek to last byte (previous byte)
+            Assert.assertEquals(-1, inputStream.skip(-1))
+            Assert.assertEquals((testDevSize - 1).toInt() % 0xFF, inputStream.read())
+
+            // Go back to marked position
+            inputStream.reset()
+            Assert.assertEquals(104 and 0xFF, inputStream.read())
+            Assert.assertEquals(105 and 0xFF, inputStream.read())
+            Assert.assertEquals(106 and 0xFF, inputStream.read())
+            Assert.assertEquals(107 and 0xFF, inputStream.read())
+
+        } finally {
+            testFile.delete()
+        }
+    }
+
+    companion object {
+        fun createTestFile(size: Long): File {
+            val file = File.createTempFile("etchdroid-test-", ".img")
+            val fileOutputStream = file.outputStream()
+
+            for (i in 0..size)
+                fileOutputStream.write(i.toInt() % 0xFF)
+            fileOutputStream.flush()
+            file.deleteOnExit()
+            return file
+        }
+
+        fun createTestBlockDevice(file: File, blockSize: Int): BlockDeviceDriver =
+                FileBlockDeviceDriver(file, blockSize, 0)
+    }
+}